In recent years, a portable terminal apparatus such as a smart phone becomes popular which includes a non-contact charging function and can charge a secondary battery in a non-contact manner. In order to receive electric power from a power transmission apparatus in a non-contact manner to charge the secondary battery by using the received electric power, the portable terminal apparatus (power reception apparatus) is equipped with a power reception coil, a power reception circuit and a charging circuit.
There is known an electromagnetic induction system, an electric field coupling system and the like as a system for wirelessly transmitting the electric power. For example, in the electromagnetic induction system, a power transmission coil is arranged in the power transmission apparatus and a power reception coil is arranged in the power reception apparatus to transmit the electric power through the electromagnetic induction between the power transmission coil and the power reception coil. In order to charge the secondary battery in the power reception apparatus, the power transmission apparatus transmits the electric power by using frequencies in a band of about 100 kHz-200 kHz.
Incidentally, the surface of a thin-shape portable terminal apparatus such as a smart phone is planar. Thus, in order to place the portable terminal apparatus (power reception apparatus) on the power transmission apparatus, a top plate of a charging stand at the power transmission apparatus side is also planar (for example, refer to Japanese Unexamined Patent Application Publication No. 2009-247194).
On the other hand, the portable terminal apparatus is not the thin shape but has a thickness to a certain extent, and further is equipped with a protrusion. For example, it is necessary to ensure fall-proof performance to a certain extent in a portable electronic device (power reception apparatus) such as a portable type printer. Thus, a protector made of a rubber material or the like is mounted around the electronic device to protect a main body, of the electronic device at the time the electronic device drops.
However, if protrusions such as protectors are mounted around the device, at the time the electronic device is placed on the charging stand of the power transmission apparatus, as there are protrusions, the distance between the power transmission coil and the power reception coil becomes long, and the electric power transmission cannot be efficiently executed.
There is an electronic device, including protectors, which mounts a module into which the power reception coil is incorporated in a manner of protruding to the bottom of the electronic device, forms a recessed part on the charging stand of the power transmission apparatus, arranges the power transmission coil in the recessed part, and fits the module into the recessed part (refer to Japanese Unexamined Patent Application Publication No. 2013-55779).